FINE DISSECTION ELECTROSURGICAL DEVICE

• US 20120203219A1
• Filed: 02/09/2011
• Published: 08/09/2012
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Tetzlaff, Philip M., Aluru, Rajitha, Woloszko, Jean, Goode, Johnson E., Evans, Doug, Foster, Michael D.
• Granted Patent: US 9,168,082 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 2018/00583 Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00589 Coagulation
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

An electrosurgical wand. At least some of the illustrative embodiments are electrosurgical wands including an elongate shaft that defines a handle end and a distal end, a first discharge aperture on the distal end of the elongate shaft, a first active electrode of conductive material disposed on the distal end of the elongate shaft, the first active electrode has an edge feature, a first return electrode of conductive material disposed a substantially constant distance from the first active electrode, and an aspiration aperture on the distal end of the elongate shaft fluidly coupled to a second fluid conduit.

Claims

1. An electrosurgical wand comprising:

an elongate shaft that defines a handle end and a distal end;

a connector comprising a first and second electrical pins;

an insulative sheath characterized by a plurality of discharge apertures on the distal end of the elongate shaft, the plurality of discharge apertures fluidly coupled to a first fluid conduit, and the first fluid conduit within the elongate shaft;

a first active electrode of conductive material disposed on the distal end of the elongate shaft, the first active electrode has an edge feature, and the first active electrode electrically coupled to the first electrical pin;

a first return electrode of conductive material, the first return electrode comprising an extended feature disposed a substantially constant distance from a distal apex of the first active electrode, and the first return electrode electrically coupled to the second electrical pin; and

an aspiration aperture on the distal end of the elongate shaft fluidly coupled to a second fluid conduit, the second fluid conduit within the elongate shaft.

2. The electrosurgical wand of claim 1 wherein the edge feature is at least one selected from the group consisting of:

a scalloped portion, a cut, a divot, and an asperity.

3. The electrosurgical wand of claim 1 wherein the edge feature comprises a cut, the cut has a diameter and a depth on each side between and including 0.008 and 0.012 inches.

4. The electrosurgical wand of claim 1 wherein the edge feature comprises a cut, the cut has a diameter and a depth on each side of 0.010 inches.

5. The electrosurgical wand of claim 1 wherein the edge feature comprises a first and second cut disposed on opposed sides of the first active electrode.

6. The electrosurgical wand of claim 1 wherein first active electrode further comprises a loop of wire.

7. The electrosurgical wand of claim 6 wherein the loop of wire has a diameter between and including 0.025 and 0.035 inches.

8. The electrosurgical wand of claim 6 wherein the loop of wire has a diameter of 0.030 inches.

9. The electrosurgical wand of claim 1 wherein the first active electrode has an exposed standoff distance from a non-conductive spacer of 0.080 inches.

10. The electrosurgical wand of claim 9 wherein the non-conductive spacer comprises a step feature operable to limit a tissue penetration depth of the first active electrode.

11. The electrosurgical wand of claim 1 wherein the extended feature comprises a tab.

12. The electrosurgical wand of claim 1 wherein the plurality of discharge apertures are fluidly coupled to a plurality of fluid flow channels disposed in an annular gap between the insulative sheath and the elongate shaft.

13. The electrosurgical wand of claim 1 wherein the plurality of discharge apertures encircle the elongate shaft.

14. The electrosurgical wand of claim 1 wherein the plurality of discharge apertures are spaced proximally from a distal-most tip of the first return electrode.

15. The electrosurgical wand of claim 1 wherein the aspiration aperture is offset from a plane that bisects the thickness of the distal end of the elongate shaft.

16. The electrosurgical wand of claim 1 wherein the aspiration aperture defines an aperture width, and wherein a spacer fluid conduit transitions in width from the aperture width to a fluid conduit opening width not less than half an internal diameter of the shaft.

17. The electrosurgical wand of claim 16 wherein the spacer fluid conduit further transitions in depth from an aspiration chamber depth not less than half a thickness of a non-conductive spacer to a fluid conduit opening depth.

18. A system comprising:

an electrosurgical controller, the electrosurgical controller configured to produce radio frequency (RF) energy at an active terminal with respect to a return terminal;

an electrosurgical wand coupled to the electrosurgical controller, the electrosurgical wand comprising;

an elongate shaft that defines a handle end and a distal end;

an insulative sheath characterized by a plurality of discharge apertures on the distal end of the elongate shaft, the plurality of discharge apertures fluidly coupled to a first fluid conduit, and the first fluid conduit within the elongate shaft;

a first active electrode of conductive material disposed on the distal end of the elongate shaft, the first active electrode has an edge feature, and the first active electrode electrically coupled to the first electrical pin;

a first return electrode of conductive material, the first return electrode comprising an extended feature disposed a substantially constant distance from a distal apex of the first active electrode, and the first return electrode electrically coupled to the second electrical pin; and

an aspiration aperture on the distal end of the elongate shaft fluidly coupled to a second fluid conduit, the second fluid conduit within the elongate shaft.

19. The electrosurgical wand of claim 18 wherein the edge feature is at least one selected from the group consisting of:

a scalloped portion, a cut, a divot, and an asperity.

20. The electrosurgical wand of claim 18 wherein the edge feature comprises a cut, the cut has a diameter and a depth on each side between and including 0.008 and 0.012 inches.

21. The electrosurgical wand of claim 18 wherein the edge feature comprises a cut, the cut has a diameter and a depth on each side of 0.010 inches.

22. The electrosurgical wand of claim 18 wherein first active electrode further comprises a loop of wire.

23. The electrosurgical wand of claim 22 wherein the loop of wire has a diameter between and including 0.025 and 0.035 inches.

24. The electrosurgical wand of claim 22 wherein the loop of wire has a diameter of 0.030 inches.

25. The electrosurgical wand of claim 18 wherein the first active electrode has an exposed standoff distance from a non-conductive spacer of 0.080 inches.

26. The electrosurgical wand of claim 18 wherein the extended feature comprises a tab.

27. The electrosurgical wand of claim 18 wherein the plurality of discharge apertures are fluidly coupled to a plurality of fluid flow channels disposed in an annular gap between the insulative sheath and the elongate shaft.

28. The electrosurgical wand of claim 18 wherein the plurality of discharge apertures encircle the elongate shaft.

29. The electrosurgical wand of claim 18 wherein the plurality of discharge apertures are spaced proximally from a distal-most tip of the first return electrode.

30. The electrosurgical wand of claim 18 wherein the aspiration aperture is offset from a plane that bisects the thickness of the distal end of the elongate shaft.

31. A method comprising:

flowing a conductive fluid within a fluid conduit disposed within a electrosurgical wand, the conductive fluid discharges through a plurality of discharge apertures and flows past a return electrode disposed distally from the fluid conduit, and is then discharged over an active electrode;

applying electrical energy between the active electrode and the return electrode;

forming, responsive to the energy, a localized plasma proximate to an edge feature disposed on the active electrode;

ablating, by the localized plasma, a portion of a target tissue proximate to the edge feature; and

heating, responsive to the energy, the target tissue proximate to a smooth feature disposed on the active electrode at locations spaced away from the edge feature to thereby provide concomitant hemostasis.

32. The method of claim 31 wherein flowing further comprises flowing the conductive fluid such that the conductive fluid is discharged at least partially toward the active electrode in the form of loop of wire.

33. The method of claim 31 further comprising aspirating through a fluid conduit in the electrosurgical wand, the aspirating distal to the plurality of discharge apertures.

34. The method of claim 31 wherein the return electrode comprises an extended feature disposed a substantially constant distance from a distal apex of the active electrode.

35. An electrosurgical wand comprising:

an elongate shaft that defines a handle end and a distal end;

a connector comprising a first and second electrical pins;

a first active electrode of conductive material disposed on the distal end of the elongate shaft, and the first active electrode electrically coupled to the first electrical pin;

wherein the first active electrode has an edge feature at a first discrete location, and a smooth feature at a second discrete location; and

a first return electrode of conductive material, the first return electrode electrically coupled to the second electrical pin.

36. The electrosurgical wand of claim 35, wherein the edge feature is operable to ablate tissue, and wherein the smooth feature is operable to heat tissue for concomitant hemostasis.

37. The electrosurgical wand of claim 35, further comprising an aspiration aperture on the distal end of the elongate shaft, wherein the aspiration aperture is located on only one side of the elongate shaft and is disposed on an inferior surface of a non-conductive spacer supporting the first active electrode.